Heating system



Jlme 18, 1940. F H, s n' nan-me SYSTEM Filed March 25, 19:55

FredericliSinilh Patented June PATENT oFFics 2,204,708 HEATING SYSTEM Frederic H. Smith, Ii averhill, Masa, assignor to Minneapolis-Honeywell Regulator Company, I, Minneapolis, Minn., a corporation of Delaware Application March 25, 1935, Serial No. 12,865

6 Claims.

This invention relates to heating systems and.

more particularly to hot water heating systems embodying a constant temperature boiler, anindirect heater associated therewith for heating water for domestic purposes and a radiator associatedtherewith for heating a room.

In this type of system, it is usual to provide a hot .water boiler, a heating means therefor which is controlled by a thermostat responsive to boiler m temperature, means for conveying hot water from the boiler to a space to be heated, on and off means in the conveying means commanded by a space thermostat for controlling the temperature of the space to be heated, and means for conveying hot water from the boiler to an indirect heater for heating waterfor domestic purposes.

This type of system gives fairly good results but it is subject to various inherent drawbacks and disadvantages for every time the on and of! means is called into action to permitthe conveyance of hot water from the boiler to the radiator's, there is bound to be a shot of hot water delivered to the radiatorsfollowed by much coolperature conditions. Also, due to the use of "on and off means in the hot water conveying means, the radiators are heated to a high degree and then allowed to cool to a low degree, giving large fluctuations in radiator temperature and consequent unevenness in room temperature.

It is therefore an object of this invention to provide a heating system of the class described wherein unevenness of radiator and room temperature is eliminated by providing a means in the heating fluid conveying means that may be modulated from one position to another under the command of a room thermostat whereby the radiators are maintained at a uniform temperature during the existence of a given condition in the room to be heated.

Another object is to provide a heating system of the class described, having a'boiler, radiators for heating a space, conveying means for conveying hot water to and from the radiators, by-

pass means around the boiler and means under the command of a room thermostat for controlling the by-pass means to, deliver water at a predetermined temperature to the radiators whereby the temperature of the radiators is maintained uniform for a given condition existing in the space to be heated.

A still further object is to provide a heating system of the class described having a boiler and an indirect heater heated thereby for heating er water, causing the existence of uneven tem- (Cl. 237-13) I I, a water for domestic purposes along with radiatorsfor heating a room, conveying means for conveying hot water from the boiler to the radiators of the room, by-pass means around the boiler and the indirect heater and control means under the command of the room thermostat for-controlling the by-pass means to deliver water of a predetermined temperature to the radiators of the room whereby the temperature of the radiators is varied according to variations in the room tem- 1 perature. I

Other objects and advantages will become apparent to those skilled in the art by referring to the accompanying specification, claims and drawing inwhich drawing there is diagrammati- 1| cally illustrated a heating system which exemplifles the preferred form of my invention.

7 Although this heating system is of general utility and may be applied to steam heating systems and hot air heating systems, it is shown for pur- 2o poses of illustration and not of limitation as ap- I plied to a hot water heating system.

In this system, l0 designates a hot water boiler of the usual construction which isheated by an 4 electrically driven oil burner II. The electrically 25 driven oil burner l I has the usual safety switches and control mechanism therefor located in the control box l2, located on the oil burner ll. Mounted in the boiler I0 is a condition responsive device I3 preferablyin the form of a thermostatic device which is old in the art and needs no further explanation at this point. The thermostatic control device l3 operates a mercury switch ii that has the usual electrodes to be engaged by mercury upon the tilting of the switch 14. 33

Line wires l5 and I6 lead from some power source not shown and wire I5 is connected by meansof wire H to one of the electrodes of the -mercury switch H of the thermostatic control device I3. The other electrode of mercury switch It is connected by means of a wire iii to the oil burner control I! which in turn is connected by means of a wire is to the line wire I5. I

With these parts in the position as shown in the drawingpthe mercury switch I4 is closed because of low temperature conditions existing in the boiler. When the mercury switch I4 is so closed, energy is delivered from the line wire i5 through wire I'I, mercury switch l4, wire l8, controller I2 and wire l9 back to the line wire [6 to 50 operate the electrically operated oil burner ll.

stop the oil burner I I. By means 01 this thermostatic control element II which controls the operation of the oil burner I I, the heating fluid in the boiler i3 is maintained at a substantially constant temperature. A pipe 23' leading to an expansion tank or like device is connected into the hot water header 23 to permit the expansion and contraction of the water in the system in a. manner well known in the art.

Connected to the upper portion of the boiler i3 is a hot water supply header 23 and connected to the lower portion oi the boiler i3 is a return water header 2i. nated at 23 and is connected to the boiler i3 preferably by means of a pipe 22 connected to the hot water supply header 23 and a4pipe 24' connected directly to the lower portion of the boiler l3. It is conceivable that the pipe 22 instead of being connected to the hot water supply header 23 may be connected to the upper portion of the boiler i3 and the pipe 24 instead 01' being directly connected to the lower portion oi. the boiler i3 may be connected to the return header 2|. Located in the pipe 24 leading from the indirect heater 23 to the boiler i3 is a check valve 24' which opensdownwardly to permit the flow of water from the indirect heater 23 to the boiler i3 and prevents flow of water from the boiler i3 therethrough to the indirect heater 23.

Located in the indirect heater 23 is a coil 25, one end of which is connected by means of a pipe 23 to the upper end of a storage tank 23 and the lower end of which is connected by means of a pipe 21 to the lower end of the storage tank 28.

Water is supplied to the storage tank 23 by means of a pipe 23 connected to a cold water supply 33 and hot water for domestic purposes is drawn from the storage tank 23 by means 01' a pipe 3| connected to a hot water supply pipe 32. A cold water riser 33 is connected to the cold water supply pipe 33 whereby cold water may be supplied to a point of use such as a sink 31 through the cold water faucet 34. Hot water is obtained from the hot water supply'pipe 32 through a hot water riser 35 and the hot water faucet 33 for use at a point such as the sink 31.

Due to the fact that the temperature of the boiler water in the boiler i3 is maintained constant, the temperature of the heating water in the indirect heater 23 is also maintained constant to maintain constant the temperature of the domestic water located in the storage tank 23 which provides for hot water at a constant temperature at all times for domestic purposes.

Connected to the return pipe 2i is a by-pass pipe 43 which leads upwardly therefrom to a three-way mixing valve generally designated at 4i. This three-way mixng valve 4| has a hot chamber 42 and a cold chamber 43 which are separated from each other by a suitable partition. The chambers 42 and 43 are provided with ports 44 and 45 respectively which open into a mixing chamber 43. Slideably mounted in the mixing chamber 43 is a control valve 41 which may take the form of a slide valve to control the relative openings of ports 44 and 45. The valve and ports are so arranged that when port 45 is fully closed. port 44 is fully open and when port 44 is fully closed, port 45 is fully open. Movement of the valve 41 between these extreme positions opens ports 44 and 45 more or less depending on the position of the valve 41. By this construction, more or less water from the hot water supply pipe 23 or more or less cold water from An indirect heater is desig-' the by-pass pipe 43 is admitted to the mixing chamber 43. V

Connected into the mixing chamber 43 is a pipe or header 43 to which are connected risers 43, only one of which is shown in the drawing. Connected to the riser 43 is a pipe '53 leading into a heat exchanger, preferably in the form of a radiator II which is provided with the usual air vent 52. The pipes 33 may contain orifices therein whereby the proportionate amount of heating fluid delivered to the various radiators may be determined. Leading from the heat exchanger or radiator i is a pipe 53 connected to a return riser 54 which in turn is connected to a return pipe 55 ior returning the heating fluid from the radiator to the boiler. Located between the return pipe 55 and the return pipe 2i and ahead of the by-pass pipe 43 is a motor operated circulating pump 53 which, in this preferred form of the invention, is constantly energized during the time the heating system is in operation. Although a circulating pump is shown and described, heating fluid could be circulated through the system by gravity. The circulating pump, however, insures circulation and better performance. A check valve 2| is located in the return header 2| between the boiler i3 and the by-pass pipe 43 to prevent the flow of hot water from the boiler i3 through the header 21 into the by-pass pipe 43.

The motor operated circulating pump 53 is energized by means of wires 51 and 53 which are connected to the line wires l5 and I3 and wires 53 and 33 which are connected respectively with the wires 51 and 53 and the motor operated circulating pump 55. As long as energy is being supplied to the line wires l5 and ii, the motor operating circulating pump 53 is maintained in operation.

Due to the fact that the motor operated circulating pump 53 is not started and stopped to eifect a control in this system, it may be of lighter weight and construction since it is not sub- Ject to the usual severe starting torques. However, if it is desirable to start and stop the motor operated circulating pump 53 under the control of some condition, it is within the contemplation of this invention to have it so started and stopped.

Referring now to the heating system as it relates to supplying heat to the radiator 5i, a closed system is provided from the boiler i 3 by means of the hot water header 23, three-way mixing valve 4!, pipe 43, riser 43, pipe 53, radiator 5i, pipe 53, return riser 54, return pipe 55, circulating pump 56 and return pipe 2i back to the boiler i3. Heating fluid is preferably circulated through this closed system by means of the circulating Dump 56.

By reason of the by-pass pipe 43 being connected to the return pipe 2i and to the threeway mixing valve 4i some or all of the heating fluid so circulated by the circulating Dump 53 may be by-passed through the by-pass pipe 43 around the boiler 13. By suitably manipulating the slide valve 41 of the three-way mixing valve 4i to vary the effective sizes of the port openings 44 and 45, more or less water may be delivered from the hot water header 23 and from the by-pass pipe 43 into the hot water pipe 43. Upon raising the valve 41, more cool by-passed water from the by-pass 43 is allowed to enter the pipe 43 and less hot water from the boiler I3 is allowed to enter the pipe 43. By lowering the valve 41, reverse action takes place. permitis disclosed in the Cunningham patent, specific a o-woe tribution to the heat exchangers or radiators 5i.

The valve 41 of the three-way. mixing valve 4| is moved in any number of given positions with respect to the ports 44 and 45 by means of a proportioning motor 63 which may be of the type shown and described in detail in U. S. Patent 1,989,972 granted to Lewis L. Cunningham on Feb. 5, 1935.. Since the manner of operation of this proportioning motor 68 is completely reference thereto is notdeemed necessary, it

being sufiicient to state that the valve 41 is moved upwardly'and downwardly by means of a -rack 64 and a pinion 65 associated therewith which is operated by the proportioning motor 63.

'The proportioning motor 63 receives its energy by means of wires 6i and 62 connected respectively .t'o wires 51 and 58 which in turn are con nected respectively to wires i5 and I6 leading to a source of power not shown. The proportioning motor 63 is controlled and positioned by means of a control mechanism preferably in the form of a thermostat designated at 66. This thermostat 66 operates a slider arm over a potentiometer coil 6'! to effect the variation and positioning of the proportioning motor 63. The thermostat is connected by means-of wire 68 and each end of the potentiometer coil 61 is connected by means of wires 69 and .10 to the proportioning motor 68.

Upon an increase in temperature in the room v or space to be heated, the thermostat 66 will be efiected to slide the potentiometer slider across the potentiometer coil 61 to vary the resistances thereof to move the proportioning motor 63 a given amount which movement is reflected by means of rack 64 and pinion 65 to operate the a constant temperature is always supplied. .As-

suming that the temperature in the room or space to be heated falls below a predetermined value, thermostat 66 will move its slider from the v position shown to the left, varying the resistance in the potentiometer coil 61 which operates the proportioning motor 63 in. the manner described 7 in the Cunningham patentjto rotate the pinion 65 to lower the rack 64 and the slide valve 41. Such lowering of the slide valve 41 increases the effective size of the port opening 44 and decreases the effective size of the port opening 45, permitting more hot water from the boiler iii to enter the pipe 48 and permitting less cooler water from the by-pa'ss pipe 48 from entering the pipe 48. Bay reason of this, the temperature of the water delivered into the pipe 48 is increased and when said water is sent to the'heat exchangers or radiators 5| by the operation of thecirculating pump 56, the temperature of the radiators 5| will be increased a like amount to restore the room temperature to the desired value.

If the temperature in the room increases above a desired value, the thermostat 66 will move the slider 61 from the left to theright over the potentiometer coil 51' to vary the resistances therein to position the proportioning motor 68 to rotate the pinion 65 to raisethe rack 64 and the valve 41 thereby decreasing the eflective size of the port opening 44 and increasing the effective size of the port opening 45.. By this movement,

' more cool by-passed fluid from the by-pass pipe 48 is allowed to enter the pipe 48 and less warm fluid from the boiler i8 is allowed to enter the pipe 48 to decrease the temperature of the heating fluid in pipe 48. By reason of this decrease in temperature of the heating fluid in the pipe 48 and a consequent decrease in temperature in' the radiators or heat exchangers ii, the room temperature will fall to the desired point.

By reason of the fact that the valve 41 is positioned in any number of positions w th respect to the port openings 44 and 45 unde the command and direction of the room thermostat 66,

there is a modulating effect brought about for controlling the temperature of the hot water in the pipe 48 and in the radiators 5|. By reason of this modulating or proportioning control, the temperature in the radiator 5| varies exactly as thedemand for heat varies and consequently the room heated thereby is maintained more uniform than if a purely on and off? control were used for controlling the temperatures in the radiator 5|.

By use of the by-pass pipe 40, heavy drags on the boiler III are eliminated which prevent frequent starting and stopping of the oil burner II which tends to maintain the temperature of the heating fluid in boiler l8 constant. It is conceivable and also within, the contemplation of this invention that the three-way mixing valve 4| qmay be located in the connection between the by-pass pipe 40 and the return pipe 2|. Such a location would operate'just as effectively and efliclentlyas the location illustrated. Also, it is within the contemplation of this invention to locate the circulating pump 56 in the supply pipe 48 to eflect circulation of the heating fluid through the system. -Such a location of the circulating pump 56 would be just as effective as the location illustrated in the drawing.

While one embodiment of the present invention has been shown and described in detail, many modifications will occur to those skilled in the art. It is intended in this application to cover all such modifications that fall within the scope of this invention as defined by the appended claims.

I claim as my invention:

1. In a heating system for heating a space, in combination, a boiler for heating a heating medium for said space, said boiler having an inlet and an outlet, a heat exchanger in heat exchange relationship with said space, conduit means for connecting said boiler inlet and outlet with said heat exchanger, a recirculating conduit associated with said conduit means for recirculating a portion of said heating medium through said heat exchanger without returning it to said boiler, valve means for controlling the proportions of heated medium from said boiler and recirculated medium passed through said heat exchanger, motor means for positioning said valve means, thermostatic means influenced by the temperature in said space for controlling said motor means in a manner progressively to increase in the proportion of heated medium from said boiler which is passed through said heat exchanger as the space temperature decreases and progressively to decrease in the proportion of heated medium which is passed through said heat exchanger as the space temperature increases, heating means 15 for said boiler, and means responsive to the temperature of said boiler for placing said heating means into'operation when boiler temperature falls to a predetermined low value, and for placing said heating means out of operation when boiler temperature rises to a higher value.

2. Ina heating system for heating a space, in combination, a boiler for heating a heating medium for said space. said boiler having an inlet and an outlet, a heat exchanger in heat exchange relationship with said space, conduit means for connecting said boiler inlet and outlet with said 'heat exchanger, a recirculating conduit associated with said conduit means for recirculating a portion of said heating medium through said heat exchanger without returning it to said boiler, circulation control means for controlling the proportions of heated medium from said boiler and recirculated medium passed through said heat exchanger to thereby control the temperature of the medium flowing through said heat exchanger, thermostatic means influenced by space temperature for controlling said circulation control means in a manner progressively to increase the proportion of heated medium passed through. said heat exchanger as the space temperature decreases and progressively to decrease the proportion of heated medium passed through said heat exchanger as space temperature increases, heating means for said boiler, and means responsive to the temperature of said boiler for placing said heating means into operation when boiler temperature falls to a predetermined low value and for placing said heating means out operation when boiler temperature rises to a higher value.

3. In a combined heating system for heating a building and for supplying domestic hot water thereto, in combination, a boiler having an inlet and an outlet, a heat exchanger connected to said boiler in a manner to cause a circulation oi boiler heating medium therethrough, said heat exchanger providing for heating said water, a building heat exchanger for heating said building, conduit means for connecting said boiler inlet and outlet with said building heat exchanger, a recirculating conduit associated with said conduit meansfor recirculating a portion of said heating medium through said building heat exchanger without returning it to said boiler, circulation control means for controlling the proportions of heated medium from said boiler and recirculated medium passed through said building heat exchanger to thereby control the temperature of the medium flowing through said building heat exchanger, thermostatic means influenced by space temperature for controlling said circulation control means in a manner to increase progressively the proportion of heated! medium passed through said heat exchanger as the space temperature decreases and to decrease progressively the proportion of heated medium passed through said building heat exchanger as space temperature increases, heating means for said boiler, and means responsive to the temperature of said boiler for placing said heating means into operation when boiler temperature falls: to a predetermined low value and for placing said heating means out of operation when boiler temperature rises to a higher value.

4. In a heating system for heating, a space, in combination, a boiler for heating a heating medium for said space, said boiler having an inlet and an outlet, a heat exchanger in heat exchange relationship with said space, conduit means for connecting said boiler inlet and outlet with said heat exchanger, 91 recirculating conduit associated with said conduit means for recirculating motor means in a manner to increase in the proportion of heated medium from said boiler which is passed through said heat exchanger as the space temperature decreases and to decrease in the proportion of heated medium which is passed through said heat exchanger as the space temperature increases.

5. In a combined heating system for heating a building and for supplying domestic hot water thereto, in combination, a boiler having an inlet and an outlet, a. heat exchanger connected to said boiler in a manner to cause a circulation of boiler heating medium therethrough, said heat exchanger providing for heating said water, a building heat exchanger for heating said building, conduit means for connecting said boiler inlet and outlet with said building heat exchanger, a recirculating conduit associated with said conduit means for recirculating a portion of said heating medium through said building heat exchanger without returning it to said boiler, circulation control means for controlling the proportions of heated medium from said boiler and recirculated medium passed through said building heat exchanger to thereby control the temperature of the medium flowing through said building heat exchanger, thermostatic means influenced by space temperature for controlling said circulation control means in a manner to increase the proportion of heated medium passed through said heat exchanger as the space temperature decreases and to decrease the proportion of heated medium passed through said building heat exchanger as space temperature increases.

6. Apparatus for controlling the heat supplied to a building by a hot water heating system from a source of heat comprising, in combination, means for continuously circulating the hot water through the heating system and the source of heat, conduit means providing a by-pass for the water around the source of heat, valve means in said conduit means, power means for operating said valve means, and remotely located means for controlling the valve operating means in response to variations in the temperature of the space in the building to be heated.

memo H. SMITH, 

